Eberline RO2 help

[Mitten66]

Hey folks!  Long time reader, first time question.  Thank you for allowing me to join the forum.  I am an amateur nuke geek interested in the subject for over 40 years.  Recently acquired an Eberline RO2 that turns out to be non-functional.  There is a single black wire disconnected from the ION chamber.  I have tried looking through the posts and researching the online manuals and pics, but to no avail can a good quality pic be found that shows the image I need to be sure of the wire's placement.  I am would also like to be able to verify that someone prior to me did not play with the meter and incorrectly wire it.  It is only for fun use not designed to be a safety device.  Thank you in advance and a shout out to my fellow Michiganders!

[UncaBuffalo]

https://www.nukeworker.com/study/instruments/manuals/RO-2_Manual.pdf

Did you look at this tech manual? Not a great copy, but...